steam power. Steam-engines in those days were not very
economical, needing four or five times as much fuel for the
same power as the engines of recent date.

It was not until 1838 that the problem was solved. On
April 23d of that year a most significant event took place.
Two steamships dropped anchor in the harbor of New York,
the Sirius and the Great Western. Both of these had made the
entire voyage under steam, the Sirius, in eighteen and a half
and the Great Western in fourteen and a half days, measuring
from Queenstown. The Sirius had taken on board 450 tons
of coal, but all this was burned by the time Sandy Hook was
reached, and she had to burn her spare spars and forty-three
barrels of rosin to make her way up the bay. The Great
Western, on the contrary, had coal to spare.

Two innovations in shipbuilding were soon introduced.
These were the building of iron instead of wooden ships and the
replacing of the paddle wheel by the screw propeller. The
screw-propeller was first successfully introduced by the famous
Swede, John Ericsson, in 1835. His propeller was tried in a
small vessel, forty-five feet long and eight wide, which was
driven at the rate of ten miles an hour, and towed a large
packet ship at fair speed. Ericsson, not being appreciated
in England, came to America to experiment. Other inventors
were also at work in the same line.

Their experiments attracted the attention of Isambard
Brunel, one of the greatest engineers of the period, who was
then engaged in building a large paddle-wheel steamer, the